Your goal is to shoot your way past meteors and alien spaceships, while remaining alive and collecting the most points for shooting other spaceships and collecting items.
To begin, click on Play Now and then on the big green button to begin playing. To move the spaceship, you can either use the keyboard: (Q to shoot missiles, E to put on your defensive orb, and W,A,S,D to move in either direction and SPACE for shooting). Alternatively, you can use your mouse or your finger to click one of the 3 buttons at the bottom (Missiles, continued shooting or protective shield), and move the spaceship by holding your left mouse button (or your finger to the screen) and moving it around.
On the top of the screen, you'll see how much health you have left (the orange bars on the left), your score in the middle and the options of turning off the music or pausing to the right.